Explosive



Patented Oct. 6, 1953 UNITED STATES PATENT OFFICE EXPLOSIVE William J. Taylor, Tamaqua,

Atlas Powder Company, corporation of Delaware Pa., assignor to Wilmington, Del., a

No Drawing. Application February 5, 1948, Serial No. 6,567

9 Claims.

The present invention relates to explosive compositions.

An object of the invention is the provision of a water resistant explosive composition containing a water soluble inorganic oxygen supplying salt.

Another object of the invention is the provision of a water resistant ammonium nitrate explosive composition.

Other objects of the invention will be apparent from the following description:

For many years water soluble inorganic oxygen supplying salts have been used in explosive compositions. Representative of such salts are the nitrates, chlorates, and perchlorates of calcium. magnesium, potassium, sodium, and ammonium. Of these, ammonium nitrate has been by far the most important, and it is indeed the principal power producing ingredient of most explosives manufactured today.

Since explosives are often used under wet conditions, the water solubility of these salts has been a distinct disadvantage. Water tends to leach them and to desensitize the explosive.

Several methods for improving the water resistance of explosive compositions containing water soluble oxygen supplying salts have heretofore been used with various degrees of success. For example, nitrocotton has been included in the compositions; the salts have been coated with water repellant materials such as paraffin, petrolatum, and rosin; and various water disperslble starch materials which form a protective gel with water have been included in the compositions.

It has been discovered in accordance with the present invention that manno-galactans are superior gel-producing ingredients in explosive compositions containing inorganic water soluble oxygen supplying salt. Manno-galactans may be obtained from several vegetable products. Locust bean gum and carob bean gum are largely mannogalactans. Guar flour, the powdered endosperm of the guar bean, is a particularly readily available mannogalactan and is preferred for use in the present invention.

Powdered manno-galactans have the property of rapidly forming an unusually stiif sol on being mixed with water. The presence of salts dissolved in the water does not materially affect the thickening properties of the manno-galactans, and the manno-galactans are not precipitated by the salts. When an explosive composition containing a water soluble inorganic oxygen supplying salt and a manno-galactan comes in contact with water, the manno-galactan absorbs water, and

apparently the resultant gel protects the ammonium nitrate, inhibiting leaching and desensitization.

Explosive compositions usually contain carbonaceous combustible ingredients. Manno-galactans, in addition to providing water protecting properties, are also an excellent source of carbonaceous combustible, and consequently may be employed in substitution for part or all of the carbonaceous combustible usually employed in explosives.

Manno-galactans may be employed very generally in the preparation of explosives containing water soluble inorganic oxygen supplying salts. They have been found particularly advantageous in compositions sensitized with explosive liquid nitric esters such as nitro glycerine and the various nitro glycerine mixtures commonly employed in the explosives industry. Ordinarily the invention will find its principal application in explosives containing higher proportions of soluble salts, as high, for example, as about On the other hand, however, the invention improves explosives containing relatively low amounts, as low as about 15%, for example, of soluble salts. The so-called ammonia dynamites are good examples of explosives in which the present invention may be advantageously employed.

Manno-galactans will usually be found to improve water resistance markedly when amounts as low as 0.4% of the explosive compositions are employed. Amounts as high as 15% are also generally satisfactory.

Explosives made in accordance with the invention may contain any of the ingredients commonly used to obtain special efiects in explosives. For example, various sensitizers or cooling salts may be employed. Also water resistant coating ingreclients may be used although such coatings are usually quite unnecessary.

Since manno-galactans absorb water by means of a surface action, it is usually desirable that the manno-galactans be employed in finely divided form. Screen sizes below mesh are usually preferred although satisfactory results may be usually obtained. when most of the material will pass a 60 mesh screen.

The invention will be further described by means of the following specific examples:

Explosive compositions were prepared by co ventional procedures to each of the formulae listed in Table I.

Each of these explosives was packed in con. ventional 1%" x 8" paper cartridges. The ends of the cartridges were sealed with tallow. The

3 wrapper of each of the cartridges was perforated with sixteen holes arranged in four longi tudinal lines equidistantly spaced around the cartridge, the holes in adjacent rows being staggered. Each cartridge was placed in a vessel, was covered with sand, and water was poured into the vessel until it stood above the. sand. The cartridges were then removed from the sand after a known number of hours, and their detonatability with a number 6 mined. The results are tabulated in Table II.

TABLE I blasting cap was deter- 16 water to impart water-resistance to said explo sive.

5. An explosive comprising granular ammonium nitrate, an explosive liquid nitric ester sensitizer, and locust bean gum flour distributed throughout said explosive in finely-divided form capable of swelling in contact with water to impart water-resistance to said explosive.

6. An explosive comprising granular ammoiiium nitrate, nitro glycerine, and locust bean gum flour distributed throughout said explosive Nitro Glycerine, percent Nitro Cotton, percent Coated Fine Ammonium Nitrate,

percents; Coated Coarse Ammonium Nitrate,

percent Fine Sodium Nitrate, percentsn nn Coarse Sodium Nitrate, percent--- Chalk, percent Fine Apricot Pit Pulp, percent.

Cca'rscnpricct Pit Pulp, percent Wood Pulp, percent Ground Sulphur, percent Corn Flour, percent Powdered Guar, percent Powdered Locust Bean Gum,

cent Ground Soft Coal, percent..-

TABLE II Ability to deioiiaie after contact with water Examples Hours Immersion It will be seen that in each case the explosive containing a manno galacta n (Examples z, 3, 4, 6, 9, and 11) exhibited greatly increased water resistance.

What is claimed is: I

An explosive comprising a granular, water soluble inorganic oxygen supplying salt, a sensitizer, and a manno-galactan distributed throughout said explosive in finely-divided form capable of swelling in contact with water to impart water-resistance to said explosive.

2 An explosive comprising a granular ammonium nitrate, an'explosive liquid nitric ester, and a powdered manno-galactan distributed throughout said explosive in finely-divided form-capable of swelling in contact with water to impart water-resistance to said explosive.

3. An explosive comprising granular ammonium nitrate, an explosive liquid nitric ester sensitizer, and guar flour distributed throughout said explosive in finely-divided form capable -'of swelling in contact with water to "impart waterresistance to said explosive.

4. An explosive comprising granular ammonium nitrate, nitro glycerin'e, and guar flour distributed throughout said "explosive "in finely divided form capable of swelling in contact with in finely-divided term capable or swelling in con ct with water to impart water-resistance to sa d explosive. I

'7. An explosive composition 'c'oin'prisinga blend of EWaLtiT-Sblfibl Solid' inorganic oxidizing "Salt, afsen's zingf'agent therefor, and guar fi'o'ur in pulverul'nt-f-orm in an amount b'etV'J'e'en'OJi and 15%.

'8. Anexplos'ive composition comprisin amend or a ate'r -soluble solid inorganic oxidizing salt, s n'siti'zing agent "therefor, an a marine gala'ctan in pulve'iule'nt form ca able of swelling 'iircontact with water 0 impart water-resistance tosaid expin'sive cempo'siuon in an arnduntbetween O.4"%"a'nd'15%. I

I 9. An explosive composition"comprising'a'biehfi Of "Wate ol'uble sous inorganic oxidizing salt, a sensitizing agent therefor, and locust b'ean'g'u'rn flour in pulverulent form in an amount between 014% and 15%. I

WIIELIAM J. fleffences Cited in thefile of this patent 'tJ'NrTED 's'rA'Ins PATENTS ,Name

120,626 Feb. 4,4890

(Other references on following page) 5 UNITED STATES PATENTS Number Name Date Heinemann Jan. 28, 1913 Cook et a1. Apr. 30, 1940 Winning Mar. 23, 1943 Winning Mar. 23, 1943 Winning Mar. 23, 1943 Winning Mar. 23, 1943 Winning Mar. 23, 1943 Kirst Mar. 23, 1943 Carey Nov. 9, 1943 Carey Apr. 4, 1944 6 Number Name Date 2,358,385 Davis et a1 Sept. 19, 1944 FOREIGN PATENTS Number Country Date 537,579 Great Britain June 27, 1941 OTHER REFERENCES Hackhs Chemical Dictionary, Blakiston, 1944, page 171. (Copy in Division 43.)

Water soluble Gums," by Mantell, page 120, pub. Feb. 1947 by Rheinhold Publ. 00., N. Y. C. (Copy in Div. 63.) 

2. AN EXPLOSIVE COMPRISING A GRANULAR AMMONIUM NITRATE, AN EXPLOSIVE LIQUID NITRIC ESTER, AND A POWDERED MANNO-GALACTAN DISTRIBUTED THROUGHOUT SAID EXPLOSIVE IN FINELY-DIVIDED FORM CAPABLE OF SWELLING IN CONTACT WITH WATER TO IMPART WATER-RESISTANCE TO SAID EXPLOSIVE. 